Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Optimal Process Planning of CNG Pressure Vessel by Ensuring Reliability and Improving Die Life

CNG 압력용기의 최적 공정설계를 통한 공정의 신뢰성 확보 및 다이 수명 향상

  • Bae, Jun Ho (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
  • Lee, Hyun Woo (Research Institute of Mechanical Technology, Pusan Nat'l Univ.) ;
  • Kim, Moon Saeng (School of Mechanical Engineering, Pusan Nat'l Univ.) ;
  • Kim, Chul (Research Institute of Mechanical Technology, Pusan Nat'l Univ.)
  • 배준호 (부산대학교 기계공학부) ;
  • 이현우 (부산대학교 기계기술연구원) ;
  • 김문생 (부산대학교 기계공학부) ;
  • 김철 (부산대학교 기계기술연구원)
  • Received : 2012.12.27
  • Accepted : 2013.05.27
  • Published : 2013.07.01
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Abstract

The deep drawing and ironing (DDI) process involving the use of a high-capacity horizontal press is used for manufacturing acompressed natural gas (CNG) pressure vessel. However, some variables of the DDI process have been determined based on the experiences of workers, and the short die life needs to be improved for manufacturing the pressure vessel withhighquality and lowcost. In this study, process variables such as the draw ratio, distance between dies, radius of rounding of drawing die, and angle of ironing die are chosen to enhance the reliability and improve the die life based on previous studies and experiences. The draw ratio limits at which no tearing or wrinkling occurs are determined using FEA, and the distances between dies, radius of rounding of drawing die, and angle of ironing die are optimized by the DOE method. The results of the optimal process variables are compared with those of the existing DDI process for verifying their effectiveness.

CNG 압력용기의 제조를 위하여 고성능 수평식 프레스를 이용한 딥드로잉과 아이어닝의 연속공정(D.D.I. 공정)이 도입되었다. 그러나, 몇몇 D.D.I. 공정 변수들은 현장 경험에 의존하여 결정되는 문제점이 있으며, 다이의 짧은 수명 역시 고성능, 저비용의 압력용기 제조를 위하여 필수적으로 개선되어야 한다. 본 연구에서는, 공정의 신뢰성 확보 및 다이 수명 향상을 위하여 기존 관련 연구 및 현장 경험을 바탕으로 드로잉비, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도를 공정변수로 결정하였다. FEA 를 이용하여 각 성형 단계에서 찢어짐과 주름이 발생하지 않는 한계 드로잉비를 결정하였고, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도에 대하여 실험계획법을 이용하여 최적 공정설계를 수행하였으며, 기존 공정에 의한 결과와 비교하여 효율성을 검증하였다.

Keywords

References

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